The prior art has disclosed numerous two-dimensional illuminated displays. For instance, information and entertainment displays have been disclosed with linear and two-dimensional arrays of selectively activated light sources, such as light-emitting diodes (LEDs). Two-dimensional arrays of light sources are typically arranged in a planar configuration. A display may thus be created by selectively illuminating the light sources. In certain instances, the arrays may be movable thereby to increase the display effect. By way of example, devices of the prior art have disposed linear and two-dimensional arrays of light sources on flat and sometimes arcuate or cylindrical rotatable members, such as fan blades, rotating drums, and other structures whereby messages and animated images can be displayed over a range of angles. While advantageous in certain applications, two-dimensional arrays are obviously limited in their ability to display images and information.
Accordingly, further teachings of the prior art have sought to provide three-dimensional displays, such as by use of a two-dimensional array of light sources disposed on a rotatable panel. The array can then be rotated about a central axis while the light sources are activated in sequence and at an effective rate thereby to present an image to a viewer. The image can be a moving image or a fixed image, each being perceived by the viewer as a result of the persistence of vision phenomenon associated with the human eye. Such rotating, three-dimensional displays can provide enhanced detail to the viewer and are commonly considered to have greater appeal aesthetically and for conveying advertising and information. When such three-dimensional displays are interfaced with electronic controls, a variable three-dimensional image can be created with a degree of complexity. Such displays can be exploited for numerous purposes, including entertainment, education, and conveying three-dimensional data, such as in the fields of medicine, non-destructive testing, air traffic control, and computer aided design.
One of the earliest volumetric three-dimensional displays was designed by Schipper and was protected by U.S. Pat. No. 3,097,261. There, a rotating electroluminescent panel has an embedded high-speed light emitter array. With that, by controlling the timing of the x-y addressing of the light emitter array and the rotation of the panel, three-dimensional images can be formed within the volume swept by the rotating panel. Further three-dimensional display devices with an array of light sources retained on a rotatable flat panel are found, for example, in U.S. Pat. No. 3,154,636 to Schwertz and in the U.S. Pat. No. 4,160,973 to Berlin. Berlin sought to develop an approach to solve a recognized high-bandwidth data transmission problem using an optical link and exploiting a high speed LED matrix with the LEDs again rotated to sweep out a three-dimensional volume. A curved rotatable screen is taught in U.S. Pat. No. 3,204,238 to Skellet, and a spherical spiral screen is used in U.S. Pat. No. 3,202,985 to Perkins, both disclosed for use as radar displays. In each instance, when the panel is rotated and the light sources selectively illuminated, the two-dimensional array produces volumetric, three-dimensional displays.
In each of these systems, the resolution of the two-dimensional image or, as applicable, the three-dimensional volume is inherently limited by the number and density of LEDs or other light sources that are rotated to produce the two-dimensional or three-dimensional image. Even where light sources are disposed to opposed sides of an axis of rotation seeking to produce brighter and crisper animation, corresponding light sources will tend to travel along the same illumination paths. Therefore, while there may actually be multiple light sources in a given illumination path, the light sources will not yield an increase in the resolution of the animation provided by the system.